Decision-Making For Infants with Complex Life-Threatening Conditions Abstract Infants with life-threatening conditions who earlier would have died in the first months of life are now receiving highly complex and sometimes experimental treatments designed to cure the condition or prolong life. However, these treatments have uncertain outcomes, the infants are at high risk for death, and if they live face a life-span of significant morbidity. Infants with these conditions experience an uncertain trajectory that typically involves multiple health crises requiring parents and health care providers to make critical decisions about the type and level of treatment. Decisions span the continuum from whether to initiate treatment, how to alter the treatment to respond to a medical crisis, whether to shift from aggressive curative care to symptom- focused palliative care, to whether to withdraw treatment. This 5-year study will use a longitudinal, case study design to examine the trajectory of decision making for infants undergoing life-sustaining treatment for complex life-threatening conditions (CLTC). Three groups of infants with CLTCs who are at particularly high risk for death and significant life-span morbidity are the focus of this study: extremely preterm infants (<26 weeks gestation), infants with complex cardiac anomalies, and infants with genetic diagnoses requiring a hematopoietic stem cell transplant (HSCT). Forty cases will be studied and each case will include the infant, parents, providers and the physical context of caregiving. Narrative interviews and self-report measures will be used with case members following birth or diagnosis and at least monthly thereafter until death or 1 year following enrollment. A within-case and cross-case analysis will be used to explore the trajectory of decision making for these infants and examine how and when decisions are across the illness trajectory. The study will identify transition points across the trajectory and identify factors influencing decision making, such as the level of involvement that parents' want; characteristics of parents who desire more or less involvement; and roles health care providers can play in decision making. The findings will be used to develop typologies of decision making and illness trajectory transition points for infants with CLTCs. These will provide a foundation for developing interventions to facilitate the decision making for these infants. PUBLIC HEALTH RELEVANCE: This study will use a longitudinal multiple case study design to examine the trajectory of decision making for infants with complex life-threatening conditions (CLTC) and influences on parents' decision making from birth or diagnosis until death or 12 months. This study will be the first study to prospectively examine the trajectory of all types of health-related decisions (treatment initiation and intensification, shifts in treatment from curative care to palliative care, withholding or withdrawing treatment) across a year-long illness trajectory, in multiple populations of infants with CLTCs, both those who die and those who survive. In addition, the sample of extremely premature infants (<26 weeks gestation), infants with complex congenital heart disease (CHD), and infants with genetic diagnoses requiring a hematopoietic stem cell transplant (HSCT) will allow for exploration of how decision making is both similar and different for infants undergoing experimental treatment for the three most common causes of pediatric death. We will identify transition points across the trajectory of decision making and identify the influences on decision making, such as the level of involvement that parents' want; characteristics of parents who desire more or less involvement; and roles health care providers play in decision making. The goal will be to identify transition points across the trajectory and provide a foundation for developing interventions to facilitate parents' decision-making for these infants.